Optical stimulation of neurons in the brain based on optogenetic targeting of specific neurons is the next big thing in neuroscience. The technique makes it possible to stimulate specific neurons by light of a certain wavelength. Different stimulation devices are on the market today. However, these devices have some limitations.
A first group of state of the art stimulation devices uses probes with optical stimulation sites located on the probes, optically connected to optical fibers. These probes are inserted in the brain and the optical stimulation sites are used to stimulate particular areas of the brain. To couple light into the probe, optical fibers are attached to the probe. The use of optical fibers may pose problems as they can be bulky. A first problem is the compactness of the device, which is reduced due to the attachment of optical fibers to a probe. The problem increases when multiple optical fibers are connected to the probe to stimulate nervous tissue with light of multiple wavelengths. A second problem is the connectivity between the probe and the optical fiber. It requires a special connection in order to couple light efficiently in the probe (e.g., the angle in which the light enters the probe needs to be correct). Thus, specific, bulky connectors are necessary which increase the size and the cost of the device.
A second group of state of the art stimulation devices uses probes with optical sources positioned on the probes. The light of the optical source is coupled into the probes to stimulate specific regions of the brain. The problem with these devices is undesired heating, which is generated by the optical source. As the optical sources are positioned on the probes, the neurprobes tend to heat up. As a result, nervous tissue near the probe tends to heat up, resulting in tissue damage and unwanted side effects.
A different issue that arises with current state of the art optical neural stimulation devices is the reusability factor. Current optical probes are usually used only once and cannot be reused. After stimulation, the probe is disposed.
There is a need for stimulation devices that can overcome at least one of the drawbacks mentioned above.